1. Field of the Invention
Embodiments of the invention generally relate to flow analysis.
2. Description of the Related Art
Oil and/or gas operators periodically measure water/oil/gas phase fractions of an overall production flow stream in order to aid in improving well production, allocating royalties, properly inhibiting corrosion based on the amount of water and generally determining the well's performance. Various approaches for analyzing the phase fraction of such flow streams exist and include full or partial phase separation and sensors based on capacitive, density and microwave measurements. However, known measurement techniques suffer from their own unique drawbacks and/or limitations.
Wells often produce water along with hydrocarbons during normal production from a hydrocarbon reservoir within the earth. The water resident in the reservoir frequently accompanies the oil and/or gas as it flows up to surface production equipment. Onset of water in gas wells and wet gas wells introduces the prospect of ice-like hydrate formation, which can plug lines and create unsafe flowing conditions. Water in the production flow at low temperatures such as less than 15° C. as occurs in seawater applications may cause formation of the hydrates depending on volume and pressure of the flow. Furthermore, gas wells that are often high rate produce large pressure drops across chokes and flow area changes. At these locations, Joule Thompson cooling can reduce temperatures significantly which may result in severe hydrate problems in a matter of hours or even minutes if water is present. Serious problems result once the hydrates form and block or limit flow. Continuous measurement of phase fraction rather than, for example, monthly testing can improve operations such as hydrate prevention as well as reservoir management and allocations.
Some approaches utilize chemical injection to inhibit gas hydrate formation in case of any potential water breakthrough that may not be detected. However, cleaning and treatment procedures required at surface to remove the hydrate inhibitor along with high costs of the inhibitor itself contribute to production expenses. Therefore, injection of methanol as an exemplary hydrate inhibitor unnecessarily increases costs when preformed even if water is not present or when done at levels beyond that required based on the water that is present.
Therefore, there exists a need for an improved water detector and overall phase fraction measurement to enable, for example, flow assurance, improved reservoir management, and improved allocation from a producing well. There exists a further need for an improved infrared optical detector, such as a water detector that provides the flow assurance or other flow related information with improved sensitivity and accuracy.